Outside micrometer



0, 1953 J. A. SII'EDMAN 2,625,745

OUTSIDE MICROMETER Filed Aug. 17, 1949 Patented Jan. 20, 1953 2,625,745 OUTSIDE MICROMETER James A. Stedman, Cranston, R. 1., assignor to Central Tool Company, a corporation Application August 17, 1949, Serial No. 110,698

2 Claims.

The present invention relates to measuring instruments, and has particular reference to a novel construction for an outside micrometer.

The principal object of the invention is to provide a precision micrometer having an adjustable fixed jaw and a movable slide jaw.

Another object of the invention is to provide a frictionless connection between a micrometer slide jaw and a manually operated micrometer screw.

With the above and other objects and advantageous features in view, the invention consists of a novel arrangement of parts more fully disclosed in the detailed description following, in conjunction with the accompanying drawings, and more specifically defined in the claims appended thereto.

In the drawings,

Fig. l is a side elevation of an outside micrometer embodying the novel construction;

Fig. 2 is an end view thereof, partly broken away;

Fig. 3 is a sectional detail, partly broken away, on the line 3-3 of Fig. 1;

Fig. 4 is an enlarged section on of Fig. 2.

It has been found desirable to provide a precision instrument for measuring large outside diameters or widths, for example, within a range from one to six inches. To this end, I provide an elongated base on which one micrometer jaw is adjustably set for an initial width, and on which a cooperating micrometer jaw is mounted for sliding movement, the sliding jaw being moved by manually rotating a standard type Vernier micrometer screw. I have further mounted a novel frictionless connection between the mi crometer screw post and the sliding jaw, to provide exact correspondence between rotation of the screw and linear movement of the sliding jaw.

Referring to the drawings, the micrometer H] includes a base i I, an adjustable fixed jaw l2, and a slidable jaw E3. The base I l is accurately machined, preferably to rectangular cross-section, see Fig. 3, and has a series of precisely spaced openings I4, the preferred spacing being one inch apart. The jaw l2 includes a body 15, which has a rectangular slot 16 for slidably seating over the base H, and the jaw 12 has tapered extension I! which has a finished contact side face it. A lock screw 19 is seated in a threaded passageway 20 in the body I for manual setting to lock with the lower edge of the base, and the body l5 has a transverse bore 2| for aligning with a selected base opening 14, a lock pin 22 being passed the line 2-4 through the bore 2| and the selected opening it to set the jaw l2 at a selected distance along the base II. The lock pin 22 has a knurled finger piece 23 with a groove 24 to receive a thread or a string, which is also attached to the lock screw is.

A movable jaw i3 is similar to the fixed j but is oppositely directed, the parts of the fixed jaw I2 and the movable jaw 13 being respectively right and left handed. The movable jaw l3 has a body 25 which is provided with a rectangular slot 26 to slidably seat over the base I I, and includes a lock screw 21 which is seated in a transverse threaded passageway 23 similar to the passageway 20 and is adapted to releasably engage the lower edge of the base. The jaw l3 has a tapered extension 29 with a terminal finished contact face 39 directed towards the finished contact face l8 of the fixed jaw extension.

The base I I has an end bearing block 3! which extends below the lower edge of the base and has an axial passage 32 which is provided with a bearing sleeve 33 for slidably journaling the movable shaft 34 of a Vernier micrometer 35, which is of standard type with a fixed barrel 35 which is secured to the block 3i and threadedly recesses the lower end of the shaft 34, the fixed barrel having the usual length markings 3i, and a rotatable barrel 33 with cooperating Vernier indicia 38a, which is integral with the shaft 3d.

The movable shaft 34 is connected to the body 25 of the movable jaw, to slide the movable jaw towards the fixed jaw in exact correspondence to the rotary movement of the micrometer barrel 35.

The preferred connection between the shaft 3 which rotates and moves axially, and the block 25 of the movable jaw is illustrated in Fig. i. The end 39 of the shaft 34 has an axial recess til in which the cylindrical stem M of a ball-headed pin 42 seats and is locked in place by a cross key pin 43. A knurled cylindrical housing 44 has its lower end 45 reduced and machined to seat on the end of the shaft 34 and is axially bored and threaded, the bore 41 being large enough to permit insertion of the pin 42 and its ball head 45; the lower end of the bore 41 is shaped to form a bearing 48 for the ball head 46.

A stud pin 49 has its cylindrical upper portion 50 seated in a recess 5| in the body 25 in axial alignment with the'shaft 3d, the lower end 52 of the stud pin being of large diameter and threaded to seat into the bore 41, the face 53 of the lower being recessed to seat a small ball 54; the cylindrical upper portion 50 of the stud pin is locked in place by a set screw 55 seated in a transverse passage 55. When the parts are assembled as illustrated in Fig. 4 the axial movement of the shaft 34 produces a direct positive movement of the body 25 and therefore of the movable jaw, and the rotary movement of the shaft 34 is frictionless with respect to the block 2 5.

The operation of the outside micrometer is now clear. Assuming that it is desired to measure an outside dimension of an object, such as a shaft, which is more than three and less than four inches in length, the fixed jaw is set at four inches and the movable jaw is advanced by turning the micrometer screw until the dimension is seated between the two contact faces, whereupon the length of the dimension is precisely shown.

Although I have described a specific constructional embodiment of my invention, it is obvious that changes in the size, shape and arrangement of the parts may be readily made for diiferent outside measurement uses, without departing from the spirit or the scope of the invention as defined in the appended claims.

I claim:

1. A connection device for an outside micrometer having an elongated linear base, a fixed jaw secured thereto, a movable jaw slidably mounted thereon and micrometer mechanism including a movable shaft mounted on said base and connected to the movable jaw for imparting linear movement thereto along said base, comprising a sleeve adapted to be secured to the movable jaw and having a seat, and a pin having a ball head engaging said seat and having a pin end adapted to be locked to the movable shaft.

2. A connection device for an outside micrometer having an elongated linear base, a fixed jaw secured thereto, a movable jaw slidably mounted thereon and micrometer mechanism including a movable shaft mounted on said base and connected to the movable jaw for imparting linear movement thereto along said base, comprising a stud pin adapted to be locked in the movable jaw and having a threaded end, the outer face of the threaded end being recessed, a sleeve threaded to the stud pin threaded end and having a seat, a pin having a ball head engaging said seat and having a pin end adapted to be locked to the movable shaft, and a ball seated in the recessed face of the stud pin and engaging the ball head of the ball headed pin.

JAMES A. STEDMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

